Reliability Issue

[tanyacjones]

I am trying to write a program that simulates the configuration shown below, using a component reliability of 0.8 for components 1 and 2, and 0.95 for components 3 and 4. I want to print the estimate of the reliability, using 5,000 simulations. (The analytical reliability of
this system is 0.9649.) This is what I have so far however I'm getting a reliability value of 1 so I think I have gone wrong somewhere. Thanks for any help! :)

Configuration c= component

     C1-----C2
a----|       |---b
     C3-----C4

#include <cstdlib>
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <iomanip>
#include<cmath>
using namespace std;


double rand_double(double a, double b) {
	return ((double)rand()/RAND_MAX)*(b-a) + a;
}

int main()
{
	double c1,c2,c3, c4;
	int success = 0;
	int total = 5000;



	for(int i = 0; i < total; i++)
	{
		c1 = rand_double(0,1);
		c2 = rand_double(0,1);
		c3 = rand_double(0,1);
		c4 = rand_double (0,1);
		if( c1 < 0.8 || c2 < 0.8 || c3 < 0.95 || c4 < 0.95)
		{
			success++;	
		}
	}
	cout << "By simulation, reliability is " << (double)success/total << endl;
	
	
system("PAUSE");
return 0;
}

[Zhuge]

Try seeding the random number generator with srand(time(NULL)) once at the start of your program.

[tanyacjones]

Thanks for the tip! I tried doing that but the program is not compiling! :( Ive never used the srand(time(NULL)) command so I may be missing something.

#include <cstdlib>
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <iomanip>
#include<cmath>
using namespace std;


double rand_double(double a, double b) {
	return ((double)rand()/RAND_MAX)*(b-a) + a;
}

int main()
{
srand(time(NULL))
	double c1,c2,c3, c4;
	int success = 0;
	int total = 5000;



	for(int i = 0; i < total; i++)
	{
		c1 = rand_double(0,1);
		c2 = rand_double(0,1);
		c3 = rand_double(0,1);
		c4 = rand_double (0,1);
		if( c1 < 0.8 || c2 < 0.8 || c3 < 0.95 || c4 < 0.95)
		{
			success++;	
		}
	}
	cout << "By simulation, reliability is " << (double)success/total << endl;
	
	
system("PAUSE");
return 0;
}

[Zhuge]

When there are errors, you should provide them so we can figure out the problem.

[tanyacjones]

Sorry! It says " 17:16: error :'time' was not declared in this scope"